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Old 06-25-2011, 03:37 PM
old_coot88 old_coot88 is offline
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Quote:
Originally Posted by vts1134 View Post
...Are there any tubes that if removed from the set would do damage to the set if it's fired up without them?
Oh yes indeed. The horiz. oscillator. If for any reason the H.output tube loses drive, it loses the negative bias voltage* on the control grid (G1). The plate current goes through the roof and if there were no fuse the output tube could be destroyed in short order, possibly cooking the fly also. That's why there's usually a fuse there for protection.

Removing either of the vertical tubes would kill vertical sweep, which could burn a line across the screen if allowed to run that way. oc

*This voltage is developed by the G1-cathode diode action rectifying the drive signal.
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